Coupling between elliptic screw polarization modes in single-mode optical waveguides with linear birefringence and regular twist of anisotropy axes in the presence of random axis twist

An analysis is made of single-mode fiber optical waveguides with linear bir efringence and regular twist of anisotropy axes in the presence of random t wist, which shows that, in this case, the coupling of orthogonal polarizati on modes having elliptic polarization in the screw coordinate system comovi ng with twist cannot be characterized by one coupling parameter, as differe ntiated from the case where constant twist is absent. In this case, the cou pling between polarization modes is characterized by three independent para meters, which are different in nature and have different effects on the cou pling of polarization modes. An estimate is made of the domain of applicabi lity of the classical formula for the h parameter in single-mode fiber opti cal waveguides without regular twist of anisotropy axes. (C) 2000 MAIK "Nau ka/Interperiodica".